The purpose of this pilot study is to investigate and compare the effect of a mild inflammatory stimulus (typhoid vaccine) on immune response, mood and cognition in healthy volunteers compared to patients with history Major Depressive Disorder (MDD) (not currently depressed and no symptoms of depression in the past 6 months).
Study design: In this double blind randomized crossover design, each participant will receive saline injection or typhoid vaccine injection at the first study visit, and will then receive the other injection at the second study visit. All participants will undergo study procedures (clinical and imaging) in two separate sessions after each injection given at least 7 days apart (within 10-14 days). Baseline blood samples will be taken and vital signs will be measured. Participants will be asked to complete the mood questionnaires and computerized reward tasks. Then, injections of normal saline will be administered intramuscularly in the deltoid muscle. At 1.5h, 3h, 4h and 6h after the injection, the subjects will complete the mood questionnaires and vital signs will be assessed. The computer based task will be repeated at 3h. Between3h and 6h after the injection blood samples will be collected for cytokines measurement. At 4h, a structural magnetic resonance imaging (MRI), and Functional magnetic resonance imaging (fMRI) will be done. Follow up visits/calls with the patients will be set to check their physical and mood status.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
19
0.5 ml of S.typhi injection
0.5 ml of normal saline injection
Sudhakar Selvaraj
Houston, Texas, United States
Change in Inflammation as indicated by cytokines
To compare proinflammatory cytokines (e.g. IL-6, TNF-α, etc) concentration between the experimental (receiving S.typhi vaccine) and the control group (receiving normal saline).
Time frame: baseline, 3-6 hours post-injection
Change in depressed mood as indicated by Hamilton Depression Rating Scale (HAM-D) score
To compare the severity of mood symptoms (as scored on the Hamilton Depression Rating Scale) between the experimental and the control group. A score of 0-7 is generally accepted to be within the normal range (or in clinical remission), while a score of 20 or higher indicates at least moderate severity of depressive symptoms. Scores range from 0-53.
Time frame: baseline, 3-6 hours post-injection
Level of prefrontal, limbic and striatal cortex activation as indicated by fMRI
Compare prefrontal cortex response to reward anticipation between the experimental and the control group, using fMRI
Time frame: 3-6 hours post-injection
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